pneu RIPTM: A Novel Respiratory Inductance Plethysmography Monitor

Abstract

Objective pulmonary function (PF) evaluation is essential for the diagnosis, monitoring, and management of many pediatric respiratory diseases as seen in the emergency room, intensive care, and outpatient settings. In this paper, the development and testing of a new noninvasive PF instrument, pneuRIPTM, which utilizes respiratory inductance plethysmography (RIP) are discussed. The pneuRIPTM hardware includes a small circuit board that connects to the RIP bands and measures and wirelessly transmits the band inductance data to any designated wirelessly connected tablet. The software provides indices of respiratory work presented instantaneously in a user-friendly graphical user interface on the tablet. The system was tested with ten normal children and compared with an existing system, Respitrace (Sensormedics, Yorba Linda, CA), under normal and loaded breathing conditions. Under normal breathing, the percentage differences between the two systems were 2.9% for labored breathing index (LBI), 31.8% for phase angle (Φ), 4.8% for percentage rib cage (RC%), and 26.7% for respiratory rate (BPM). Under loaded breathing, the percentage differences between the two systems were 1.6% for LBI, 4.1% for Φ, 8.5% for RC%, and 52.7% for BPM. For LBI, Φ, and RC%, the two systems were in general agreement. For BPM the pneuRIPTM is shown to be more accurate than the respitrace when compared to manually counting the breaths: 13.2% versus 36.4% accuracy for normal breathing and 16.9% versus 60.7% accuracy for breathing under load, respectively.

Keywords: noninvasive; pulmonary function; respiratory inductance plethysmography (RIP); tablet.

Figures

Fig. 1

Schematic of pneuRIP™ operation

Fig. 2

pneuRIP™ box shown with an iPad

Fig. 3

Screen shot of the iPad during data collection (a). Summary screen of the four respiratory indices generated after data collection on the iPad (b). The chart breaks up the data into three temporal segments and presents mean data for each segment of the data collection cycle.

Fig. 4

Benchtop test-bed that simulates calibrated breathing patterns. Motors show eccentric spools mounted on top to simulate breathing by changing length of bands.

Fig. 5

Summarized results comparing Respitrace and the pneuRIP™ system in subjects with and without respiratory load: (a) phase angle (degrees), (b) labored breathing index (LBI), (c) RC% contribution to tidal volume, and (d) respiratory rate (BPM). Note: the histograph for actual respiratory rate is measured by manual counting of breaths throughout each individual study from data generated by the pneuRIP™ system. P < 0.01 for load versus no load. Bars are shown with standard deviations.